1. Field of the Invention
The invention relates generally to code readers and particularly to readers which sense optically discernible symbol combinations or codes, such as bar codes.
2. Discussion of the Prior Art
1. Hand-held optical character reading equipment that has been available in the past has not performed well. The reader must be positioned accurately during the entire movement across the label for a valid read to occur. Operators usually “scrub” the label with the reader rather than carefully aligning the reader on the label, and often give up and manually key the information into the terminal.
The primary reason that accurate alignment is required is that the reader uses either a linear matrix of sensing elements, say sixty-four, or a rectangular matrix of sensing elements, say fourteen by forty. The recognition algorithms typically used in these systems assume that the sensor is oriented accurately over or across the character to be read with a misalignment of less than seven degrees typically specified. The operator's guides for the present products instruct the operator to hold the reader exactly perpendicular, centered on the edge of the line to be read, not tilted, skewed, angled or rocked, and to hold this alignment during the sweep across the label. It is unsurprising that few operators use the readers in this way, and that poor read rates and dissatisfaction with the criticality of the reader alignment during scanning, have been serious problems.
2. To date, there doesn't appear to be an optical character reader (OCR) product available that realistically has the capability to be operated portably. Power consumption and circuit complexity seem to be the factors that have discouraged development in this area.
3. While there was significant competition between the use of bar code and OCR systems through the late 1970's, bar coding seems to have emerged as the preferred technology. It is quite likely that the reason for this “win” is the poor performance of the available OCR equipment. If a very good, cost effective portable hand-held OCR reader were available, OCR might again become a contender for a significant share of this large market. The biggest factors in favor of an OCR system are that the label is directly human readable and the information density is high so that minimum label space is required for the information to be presented.